New Zealand Close Call: Tethered felling machine roll over

A felling machine was traveling back up the same path he came down on, towards the tethering machine, bunching trees as he went.

At the time of the incident he was parked on, or near, a rocky outcrop and was moving wind thrown trees out of the way. As he slewed the felling head around the left side track lost traction, which caused the right track to lift off the ground. This in turn caused the felling machine to start tipping over.

The operator hit the control to get the tethering machine to increase the tethering rope tension, which momentarily held the felling machine but because it was at such a high angle it continued to tip, then rolled onto its roof, where it came to a stop. The operator exited the machine, uninjured, through the main door.

Learnings and Suggestions:

The machine was positioned incorrectly over a small rocky outcrop – it should have been above or below the small rocky outcrop to get stable footing. This was due to the operator being too complacent, as he had been working on relatively gentle slopes for most of this setting.

Need to be aware of machine position when on upset terrain and/or slewing to the side with any weight in the head.

Travelling down slope – head in front on downhill side.

When shovelling from above and throwing down hill, make 100% sure machine has stable footing.

Uphill felling – felling head downhill when adjusting line and manoeuvring or moving across slope and tracks pointed directly uphill. The key to uphill felling is having the tracks stable.

Always work as if the rope will suddenly break – ask what will happen "how do I stay safe" .

Because the operator was following procedure with keeping his cab tidy, he did not have any issues with loose objects striking him when his machine rolled over.